Process for breaking petroleum emulsions



Patented Jan. 27, 1953 PROCESS FOR BREAKING PETROLEUM EMULSION S Melvin De Groote, University City, Mo., assignor to Petrolite Corporation, a corporation of Delaware No Drawing. Application May 14, 1951, Serial No. 226,320

8 Claims.

This invention relates to petroleum emulsions of the water-in-oil type, that are commonly reierred to as cut oil, roily oil, emulsified oil, etc., and which comprise fine droplets of naturally-occurring waters or brines dispersed in a more or less permanent state throughout the oil which constitutes the continuous phase of the emulsion.

One object of my invention is to provide a novel process for breaking or resolving emulsions of the kind referred to.

Another object of my invention is to provide an economical and rapid process for separating emulsions which have been prepared under controlled conditions from mineral oil, such as crude oil and relatively soft waters or weak brines. Controlled emulsification and subsequent demulsification under the conditions just mentioned are of significant value in removing impurities, particularly inorganic salts, from pipe-line oil.

Complementary to the above aspect of the invention herein disclosed, is my companion invention concerned with the new chemical products or compounds used as the demulsifying agents in said aforementioned process or procedures, as well as the application of such chemical compounds, products, or the like, in various other arts and industries, along with the method for manufacturing said new chemical products or compounds which are of outstanding value in demulsification. See my copending application, Serial No. 226,332, filed May 14, 1951. Demulsification, as contemplated in the present application, includes the preventive step of commingling the demulsifier with the aqueous component which would or might subsequently become either phase of the emulsion, in absence of such precautionary measure. Similarly, such demulsifier may be mixed with the hydrocarbon component.

The demulsifying agent employed in the present process is the fractional ester obtained from polycarboxy acid and a nitrogen-containing diol obtained by the oxypropylation of furfurylamine. The dihydroxylated compound prior to esterification must be water-insoluble and kerosene-soluble. Momentarily ignoring certain variants of structure which will be con- 2 sidered subsequently, the demulsifier may be exemplified by the following formula:

in which R is a iuriuryl radical, and n and n are whole numbers With the proviso that n plus n equals a sum varying from 15 to n is a whole number not over 2, and R is the radical of the polycarboxy acid COOH and preferably free from any radical having more than 8 uninterrupted carbon atoms in a single group, and with the further proviso that the parent dihydroxy compound, prior to esterification, be water-insoluble and kerosene-soluble.

The structure of furiurylamine is as follows:

Attention is directed to the co-pending application of Charles M. Blair, Jr., Serial No. 70,811, filed January 13, 1949 (now Patent 2,562,878, granted August 7, 1951), in which there is described, among other things, a process for breaking petroleum emulsions of the water-in-oil type characterized by subjecting the emulsion to the action of an esterification product of a dicarboxylic acid and a polyalkylene glycol, in which the ratio of equivalents of polybasic acid to equivalents of polyalkylene glycol is in the range of 0.5 to 2.0, in which the alkylene group has from 2 to 3 carbon atoms, and in which the molecular weight of the product is between 1,500 to 4,000.

Similarly, there have been used esters oi dicarboxy acids and polypropylene glycols, in which 2 moles of the dicarboxy acid ester have been reacted with one mole of a polypropylene glycol having a molecular weight, for example, of 2,000 so as to form an acidic fractional ester. Subsequent examination of what is said herein, in comparison with the previous example as well as the hereto appended claims, will show the line 3 of delineation between such somewhat comparable compounds. Of greater significance, however, is what is said subsequently in regard to the structure of the parent diol, as compared to polypropylene glycols whose molecular weights may vary from 1,000 to 2,000.

For convenience, what is said hereinafter will be divided into five parts:

Part 1 is concerned with the preparation of the oxypropylation derivatives of the specified amine;

Part 2 is concerned with the preparation of the esters from the oxypropylated derivatives;

Part 3 is concerned with the structure of the oxypropylation products obtained from the specified amine. Insofar that such materials are dihydroxylated, there is a relationship to ordinary diols which do not contain a nitrogen atom, all of which is considered briefly in this particular part;

Part 4 is concerned with the use of the products herein described as demulsifiers for breaking water-in-oil emulsions, and

Part 5 is concerned with derivatives valuable for various purposes, including demulsification, but not specifically claimed in the instant application.

PART 1 For a number of well known reasons equipment, whether laboratory size, semi-pilot plant size, pilot plant size, or large scale size, is not as a rule designed for a particular alkylene oxide. Invariably and inevitably, however, or particularly in the case of laboratory equipment and pilot plant size, the design is such as to use any of the customarily available alkylene oxides, i. e., ethylene oxide, propylene oxide, butylene oxide, glycide, epichlorohydrin, styrene oxide, etc. In the subsequent description of the equipment it becomes obvious that it is adapted for oxyethylation as well as oxypropylation.

Oxypropylations are conducted under a wide variety of conditions not only in regard to presence or absence of catalyst and the kind of catalyst but also in regard to the time of reaction, temperature of reaction, speed of reaction, pressure during reaction, etc. For instance, oxyalkylations can be conducted at temperatures up to approximately 200 C. with pressures in about the same range up to about 200 pounds per square inch. They can be conducted. also at temperatures approximating the boiling point of water, or slightly above, as, for example, 95 to 120 C. Under such circumstances the pressure will be less than 30 pounds per square inch unless some special procedure is employed as is sometimes the case to wit, keeping an atmosphere of inert gas such as nitrogen in the vessel during the reaction. Such low-temperature-lowreaction-rate oxypropylations have been described very completely in U. S. Patent No. 2,448,- 664, to H. R. Fife, et al., dated September 7, 1948. Low temperature-low-pressure-oxypropylations are particularly desirable where the compound being subjected to oxypropylation contains one, two or three points of reaction only, such as monohydric alcohols, glycols and triols.

Since low-pressurelow-temperature reaction speed oxypropylations require considerable time, for instance, 1 to 7 days of 24 hours each to complete the reaction, they are conducted as a rule whether on a laboratory scale, pilot plant scale, or large scale, so as to operate automatically. The prior figure of seven days applies 4 especially to large-scale operations. I have used conventional equipment with two added automatic features:

(a) A solenoid-controlled valve which shuts off the propylene oxide in event that the temperature gets outside a predetermined and set range, for instance, to C.; and

(b) Another solenoid valve which shuts off the propylene oxide (or for that matter ethylene oxide if it is being used) if the pressure gets beyond a predetermined range, such as 25 to 35 pounds. Otherwise, the equipment is substantially the same as is commonly employed for this purpose, where the pressure of reaction is higher, speed of reaction is higher, and time of reaction is much shorter. In such instances such automatic controls are not necessarily used.

Thus, in preparing the various examples I have found it particularly advantageous to use laboratory equipment or pilot plant equipment which is designed to permit continuous oxyalkylations, whether it be oxypropylation or oxyethylation. With certain obvious changes, the equipment can be used also to permit oxyalkylation involving the use of glycide, wher no pressure is involved except the vapor pressure of a solvent, if any, which may have been used as a diluent.

As previously pointed out, the method of using propylene oxide is the same as ethylene oxide. This point is emphasized only for the reason that the apparatus is so designed and constructed as to use either oxide.

The oxypropylation procedure employed in the preparation of the oxyalkylated derivatives has been uniformly thesame, particularly in light of the fact that a continuous automaticallycontrolled procedure was employed. In this procedure the autoclave was a conventional autoclave made of stainless steel and having a capacity of approximately 15 gallons and a working pressure of one thousand pounds gauge pressure. This pressure obviously is far beyond any requirement as far as propylene oxide goes, unless there is a reaction of explosive violence involved due to accident. The autoclave was equipped with the conventional devices and openings, such as the variable-speed stirrer operating at speeds from 50 R. P. M. to 500 R. P. M.; thermometer well and thermocouple for mechanical thermometer; emptying outlet; pressure gauge, manual vent line; charge hole for initial reactants; at least one connection for introducing the alkylene oxide, such as propylene oxide or ethylene oxide, to the bottom of the autoclave; along with suitable devices for both cooling and heating the autoclave, such as a cooling jacket, and preferably coils in addition thereto,,with the jacket so arranged that it is suitable for heating with steam or cooling with water, and further equipped with electrical heating devices. Such autoclaves are, of course, in essence small-scale replicas of the usual conventional autoclave used in oxyalkylation procedures. In some instances in exploratory preparations an autoclave having a smaller capacity, for instance, approximately 3% liters in one case and about 1% gallons in another case, was used.

Continuous operation, or substantially continuous operation, was achieved by the use of a separate container to hold the alkylene oxide being employed, particularly propylene oxide. In conjunction with the smaller autoclaves the container consists essentially of a laboratory bomb having a capacity of about one-half gallon, or somewhat in excess thereof. In some instances a larger. bomb was used, to wit, one having a capacity of about one gallon. This bomb was equipped also with an inlet for charging, and an eductor tube going to the bottom of the container so as to permit discharging of alkylene oxide in the liquid phase to the autoclave. A bomb hav ing a capacity of about 60 pounds was used in connection with the -gallon autoclave. Other conventional equipment consists, of course, of the rupture disc, pressure gauge, sight feed glass, thermometer, connection for nitrogen for pressuring bomb, etc. The bomb was placed on a scale during use. The connections between the bomb and the autoclave were flexible stainless steel hose or tubing so that continuous weighings could be made without breaking or making any connections. This applies also to the nitrogen line which was used to pressure the bomb reservoir. To the extent that it was required any other conventional procedure or addition which provided greater safety was used, of course, such as safety glass protective screens, etc.

Attention is directed again to what has been said previously in regard to automatic controls which shut ofi the propylene oxide in event temperature of reaction passes out of the predetermined range or if pressure in the autoclave passes out of predetermined range.

With this particular arrangement practically all oxypropylations become uniform, in that the reaction temperature was held within a few degrees of any selected point, for instance, if 105 C. was selected as the operating temperature the maximum point would be at the most 110 C. or 112 C., and the lower point would be 95, or possibly 98 C. Similarly, the pressure was held at approximately pounds within a fi-pound variation one way or the other, but might drop to practically zero, especially where no solvent such as xylene is employed. The speed of reaction was comparatively slow under such conditions as compared with oxyalkylations at 200 C. Numerous reactions were conducted in which the time varied from one day to two days for the completion of the final series. In some instances the reaction takes place in considerably less time, for instance, just part of a day. The minimum time recorded in the subsequent series was 8 hours and the maximum time 14 hours. However, reactions indicated as being complete in 10 hours, for example, may have been complete in a lesser period of time in light of the automatic equipmentemployed. This applies also where the reactions were indicated as being complete in a shorter period of time, for instance, 8'h0urs.

In the addition of propylene oxide in the autoclave equipment as far as possible the valves were set so all the propylene oxide if fed continuously would be added at a rate so that the predetermined, amount would react within the first 15 hours of the 24-hour period, or two-thirds of any shorter period. This meant that if the reaction was interrupted automatically for a period of time for pressure to drop or temperature to drop the predetermined amount of oxide would still be added in most instances well within the pre determined time period. Sometimes where the addition was a comparatively small amount in a 10-hour period, there would be an unquestionable speeding up of the reaction by simply repeating the examples and using 3, 4, or 5 hours instead of 10 hours.

When operating at a comparatively high temperature, for instance, between 150 to 200 C., an unreacted alkylene oxide, such as propylene oxide, makes its presence felt in the increase in pressure or the consistency of a higher pressure. However, at a low enough temperature it may happen that the propylene oxide goes in as a liquid. If so, and if it remains unreacted, there is, of course, an inherent danger and appropriate steps must be taken to safeguard against this possibility; if need be, a sample must be withdrawn and examined .for unreacted propylene oxide. One obvious procedure, of course, is to oxypropylate at a modestly higher temperature, for instance, at to C. Unreacted oxide affects determination of the acetyl o-r hydroxyl value of the hydroxylated compound obtained.

The higher the molecular weight of the compound, i. e., towards the latter stages of reaction, the longer the time required to add a given amount of oxide. One possible explanation is that the molecule, being larger, the opportunity for random reaction is decreased. Inversely, the lower the molecular weight, the faster the reac tion takes place. For this reason, sometimes at least, increasing the concentration of the catalyst does not appreciably speed up the reaction particularly when the product subjected to oxyalkylation has a comparatively high molecular weight. However, as has been pointed out previously, operating at a. low pressure and a low temperature, even in large scale operations, as much as a week or ten days time may elapse to obtain some of the higher molecular weight derivatives from monohydric or dihydric materials.

In a number of operations the counterbalance scale or dial scale holding the propylene oxide bomb was so set that when th predetermined amount of propylene oxide had passed into the reaction the scale movement through a timeoperating device was set for either one to two hours, so that reaction continued for 1 to 3 hours after the final addition of the last propylene oxide and thereafter the operation was shut down. This particular device is particularly suitable for use on larger equipment than laboratory size autoclaves, to wit, on semi-pilot plant or pilot plant size, as well as on large scale size. This final stirring period is intended to avoid the presence of unreaoted oxide.

In this sort of operation, of course, the temperature range was controlled automatically by either use of cooling water, steam, or electrical heat, so as to raise or lower the temperature. The pressuring of the propylene oxide into the reaction vessel was also automatic, insofar that the feed stream was set for a slow continuous run which was shut off in case the pressure passed a predetermined point, as previously set out. All the points of design, construction, etc., were conventional, including the gauges, check valves and entire equipment. As far as I am aware, at least two firms and possibly three, specialize in autoclave equipment such as I have employed in the laboratory and are prepared to furnish equipment of this same kind. Similarly pilot plant equipment is available. This point is simply made as a precaution in the direction of safety. Oxyalkylations, particularly involving ethylene oxide, glyci-d'e, propylene oxide, etc., should not be conducted except in equipment specifically de-' signed for the purpose.

Ea'ample 1a The starting material was a commercial grade of furfurylamine as sold in the open market. The particular autoclave employed was one with a capacity of 15 gallons or on the average of about 7 125 pounds of reaction mass. The speed of the stirrer could be varied from 150 to 350 R. P. M.

8.37 pounds of furfurylamine were charged into the autoclave along with .75 pound of caustic the remainder of the reaction mass subjected to further oxypropylation as described in Example 42, immediately following.

E arample 4a soda. The reaction pot was flushed out with 5 nitrogen, the autoclave sealed, and the automatic 2 p u s of e r a mass d tlfi d as devices adjusted for injecting 85.25 pounds of E pl 2. pre e ms, n equlv lent to 1.68 propylene oxide in approximately a 10-hour pounds of the amine, 41.79 ptounds f p y g period. The regulator was set for a maximum of oxide, and pou of calls 8 o wer 1 25 to 35 pounds per square inch. This meant 10 jected to further oxypropylation. No additional that the bulk of the reaction could take lace, cataIyst was add d- 0.75 p unds f p pyl n and probably did take place, at a lower pressure. oxide were added without the use of any fi l- In fact, the bulk of the reaction took place at a tlonal r z y h ne q red to a d this pressure of not over 30 pounds per square inch. oun of oxide was 14 hours. The rate of add This comparatively low pressure was the result 15 tion Was about 11/2 pounds D h0ur- This eacof the fact that considerable catalyst was prestiOn Went rather Slowly at t Stage due to the ent, especially when one allows for the fact that o coh t of ca y fu-rfurylamine has substantial basicity of it own. In thlS par icular series the oxypr p l n W The addition of the propylene oxide was fairly Stopped at 131118 st e. so that the theoretical slow, about 10 or 11 pounds per hour. The addimolecular Weight s in t e eighborhood of tion was made at moderately above the boiling 3,000 the y y 1110160111841 W t in the point of water, i. e., 240 to 250 F. The initial neighborhood o 2, 0. In other Series I have introduction of propylene oxide was not made .f l lwugh pr py z OXide to ve a theoretuntil the heating devices had raised the temperm u a Weigh O 00 o 0 a d ature to somewhat above the boiling point of hlghel based on the assumption that t e e iS water, for instance, 225 to 230 F. complete reaction, with hydroxyl molecular At the completion of the reaction asample was Weights running s high as to or taken and oxypropylation proceeded as in Exhlgherample 2 immediately following, What is said hereinafter is presented in tabular E a Z M 30 form in Table 1 immediately following, with some 1: mp 5 added information as to the molecular weight 55.62 pounds of the reaction mass identified as and as to solubility of the reaction product in Example 12, preceding, and equivalent to 4.94 water, kerosene and xylene.

TABLE 1 Composition Before Composition at End 1 lax E IVIHX. N?) Amine Oxide Gata' Theo. Amine Oxide Cata Solvent T3?! 32 8 I Amt, Amt, lyst, Mol. Amt, Amt., lyst, Amt., sq. in.

lbs. lbs. lbs. Wt. lbs lbs. -lbs. lbs.

la. 5.37 .75 880 5.37 85.25 .75 758 240-250 25-35 10 2a 4.94 50. 23 .45 1,425 4.94 84.23 .45 1,140 240-250 25-35 8 3a 2. 91 49.70 .25 2,045 2.01 72.45 .26 1, 725 240-250 25-35 10 1.68 41. 72 .15 s, 025 1 5s 52. 54 .15 2,040 240-250 25-35 14 pounds of the amine, 50.23 pounds of propylene All the above examples were insoluble in water, oxide, and .45 pound of caustic soda, were allowed and soluble in both xylene and kerosene. to remain in the reaction vessel and without The final product, i. e., at the end of the oxyadtdrilngqt any Igor? catalylst subjcdcted riio reaction prglpylatign step, was a somewhat viscous liquid W1 3 poun s o propy ene 0x1 e. eoxyprowi am er to reddish-amber cast. This was py a 'fl w Conducted in Substantially the Same characteristic of all the various products obtained manner 1n regard to te hp f d Pressure from the three amines. These products were, as 111 Example 1, precedlng-i Th'ls apphes' also, 55 of course, slightly alkaline due to the residual t0 Examples 3aa/1'1d caustic soda and also due to the basic nitrogen 1:116 0x318 fg g m fi g 2 52? atom. The residual basicity, due to the catalyst. Rerwd of tune to hours 8 m e 0 a would of course be the same if sodium methylate tionwas at about 6 pounds per hour. At the end had been used. the f of the 2m f f g g Speaking of insolubility in Water or. solubility okypfopy w con mue as 85cm 6 in kerosene, such solubility test can be made m P- 0 owmg' simply by shaking small amounts of the materials Example 32 in a test tube with water, for instance, using 1% 52.87 pounds of reaction mass identified as to 5 apprczzxlmat'ely based on the amount of Example 20., preceding, and equivalent to 2.91 er fipounds of the amine, 49.70 pounds of propylene Need1ess 0 3 15 I10 j p e converoxide, and .26 pound of caustic Soda, were sion of propylene oxide into the deslred hydroxylmitted to remain in the autoclave. Without addatel compoundS- This is indicate? by them mg any more catalyst this was Subjected to that the theoretical molecular weight based on ther oxypropylation in the same manner as in a statistical average is greater than the molecuthe preceding examples. 2235 pounds f propy1 lar weight calculated by usual-methods on basis ene oxide were added. The addition was made of acetyl 0 hydroxyl Valllec y, here is in 0.1 period, The t was about 1 no completely satisfactory method for determinto 3 pounds per hour. At the end of the reaction ing molecular weights of these types of comperiod part of the sample was Withdrawn and poun s W a hi h degr accuracy When the molecular weights exceed 2,000. In some instances, the acetyl value or hydroxyl value serves as satisfactorily as an index to the molecular weight as any other procedure, subject to the above limitations, and especially in the higher molecular weight range. If any'diificulty is encountered in the manufacture of the esters, as described in Part 2, the stoichicmetrical amount of acid or acid compound should be taken which corresponds to the indicated acetyl or hydrox-yl value. This matter has been discussed in the literature and is a matter of common knowledge and requires no further elaboration. In fact, it is illustrated by some of the examples, appearing in the patent previously mentioned.

PART 2 As previously pointed out, the present invention is concerned with acidic esters obtained from the oxypropylated derivatives described in Part 1, im-

mediately preceding, and polycarboxy acids, particularly tricarboxy acids like citric and dica-rboxy acids such as adipic acid,'phtha1ic acid, or

anhydride, succinic acid, diglycollic acid, sebacic acid, azelaic acid, aconitic acid, maleic acid or anhydride, citraconic acid or anhydride, maleic acid or anhydride adducts, as obtained by the Diels-Adler reaction from products such as maleic anhydride, and cyclopentadiene. Such acids acids, unsaturated monocarboxy fatty acids, or-

unsaturated monocarboxy acids having 18 carbon atoms. Reference to the acid in thehereto appended claims obviously includes the anhydridesorany other obvious equivalents. My preference, however, is to use polycarboxyacids having not over 8 carbon atoms.

The production of esters including acid esters (fractional esters) from polycarboxy acids and glycols or other hydroxylated compounds is well known. Needless to say, various compounds may be used such as the low molal ester, the anhydride, the acyl chloride, etc. However, for purpose ofeconomy, itis customary to use either the acid or the anhydride. A conventional procedure is employed. On a laboratory scale one can employ a resin pot of the kind described in U; 8. Patent No. 2,499,370, dated March 7; 1-950, toDe Groote 8; Kaiser, and particularly with one more opening to permit the use of a porous spreader if hydrochloric acid gas is to be used as aca-talyst.

S uch device or absorption spreader consists of" minute Alundum thimbles which are connected to a glass tube. One can add a sulionic acid such as} paratoluene sulfonic acid as a catalyst. There is some objection to this, because, in some instances, there is some evidence that this acid catalyst tends to decompose or rear ange the oxypropylatcd compounds, and particularly likely to do so, if the esterification temperature is too high. In the case of polycarboxy acids suchas diglycollic acid, which is strongly acidic, there is no need to add any catalyst. The use o f hydrcl s ci ga has one d ntage over, rare.- toluene, sulfonic acid and that is that at the end at the reaction, it can be removed b f ushing out.

with nitrogen, whereas, there is no reasonably convenient means available. of removing the paratoluenew sulfonic acid or other sulfonic acid emplo ed. hy roch or c acid. s. mp oyed. one.

need only, passthe sasthroughat an xc dl is y 10 slow rate so as to keep the reaction mass acidic. Only a trace of acid need be present. I have employed hydrochloric acid gas or the aqueous acid itself to eliminate the initial basic material. My preference, however, is to use no catalyst whatsoever.

The products obtained in Part 1 preceding may contain a basic catalyst. As a general rocedure, I have added an amount of half -concentrated hydrochloric acid considerably in excess of what is required to neutralize the residual catalyst. The mixture is shaken thoroughly and allowed to stand overnight. It is then filtered and refluxed with the xylene present until the water can beseparated in a phase-separating trap. As soon as the product is substantially free from water the distillation stops. This preliminary step can be carried out in the flask to be used for esterification. If there is any further deposition of sodium chloride during the reflux stage, needless to say, a second filtration may be required. In any event, the neutral or slightly acidic solution of the oxypropylated derivatives described in Part 1 is then diluted further with sufiicient xylene decalin, petroleum solvent, or the like, so that one has obtained approximately a 40% solution. To this solution there is added a polycarboxylated reactant, as previously described, such as phthalic anhydride, succinic acid or anhydride, diglycollic acid, etc. The mixture is refluxed until esterification is complete, as indicated by elimination of water or drop in carboxyl value. Needless to say, if one produces a half-ester from an anhydride such a phthalic anhydride, no water is eliminated. However, if it is obtained from diglycollic acid, for example, water is eliminated. All such procedures are conventional and have been so thoroughly described in the literature that further consideration will be limited to a few examples and a comprehensive table.

Other procedures for eliminating the basic residual catalyst, if any, can be employed. For example, the oxyalkylation can be conducted in absence of a solvent, or the solvent removed after oxypropylation. Such oxypropylation end prodnot can then be acidified with just enough concentrated hydrochloric acid to just neutralize the residual basic catalyst. To this product one can then add a small amount of anhydrous sodium sulfate (suiiicient in quantity to take upany water that is present) and then subject the mass to centrifugal force so as to eliminate the hydrated sodium sulfate and probably the sodium chloride formed. The clear, somewhat viscous, reddish-amber to amber liquid so obtained may contain a small amount of sodium sulfate or sodium chloride, but, in any event, is perfectly acceptable for esterification in the manner described.

It is to be pointed out that the products here described are not polyesters in the sense that there is a plurality of both diol radicals and acid radicals; the product is characterized, by having only one diol radical.

Various solvents have been used but it will be noted in the examples included herewith that xylene and no other solvent has been employed. I have found xylene tobe very satisfactory. The

procedure is perfectly obvious and no further xecomplete, and itis, believed no further elaborartion is necessary.

TABLE 2 Mol. Amt. of N14311:. 131. 21155. Agual ws gi cP%ly-y 0. o. o W. yase ar ox Acid Oxy. of 3 droxyl on 1 53% Polycarboxy Reacmnt React- Ester Cmpd. H. O. H 0 Value (gm) (2111s.)

la 880 128 143 788 190 Diglycollc Acid 54. 1a 880 128 143 788 191 Aconltic acid 84. 0 1a 880 128 143 788 189 Oxalic Acid 50.5 12 880 128 143 788 101 71. 5 12 880 128 143 758 190 47. 3 2a 1, 425 78.8 98. 5 1, 140 198 Diglycolic Acid. 46. 0 2a 1, 425 78. 8 98. 5 1, 140 199 Acomtlc Acid 60; 5 2a 1, 425 78.8 98. 5 1, 140 19s 45. 9 2a 1, 425 78. s 98. 5 1, 140 200 Phthalic Anhyd a7. 5 2a 1, 425 78.8 98. 5 1, 140 201 Mal 24. 7 211 1, 425 78. 8 98. 5 1, 140 200 Oitracomc Auhyd- 28. 2 3a 2, 045 54. 9 65.0 1, 725 200 Diglycolic acid. 31.1 30 2, 045 54. 9 65. 0 1, 726 200 Aconitic Acid. 34. 4 3a 2, 045 54. 9 55. 0 1, 720 200 Oxalic acid. 20. 2 3a 2, 045 54. 9 c5. 0 1, 725 200 P1121 115 Anhyd a4. 4 3a 2, 045 54. 9 65. 0 1, 726 200 Maleic A uhydr1de 22. 8 3 2, 045 54. 9 65. 0 1, 726 202 Citracomc Anhyd.-. 26. 2 4a 3, 025 37. 1 55.0 2, 040 201 Dlglycohc Acid. 26. 4 4a 3, 025 57.1 55. 0 2, 040 205 011511 551d, 25. 3 4a 3, 025 37. 1 55. 0 2, 040 200 Acomt c Ac1d 34. 1 4a 3, 025 51.1 55. 0 2, 040 201 P5111 115 Anhydrid 29. 2 4a 3, 025 37.1 55.0 2, 040 200 Malelc Anhydnd 19. 2 4a 3, 025 37. 1 55.0 2, 040 201 Oitracomc Anhyd..- 22.0

TABLE 3 is still obscure. Such side reaction products can' A t t E contribute a substantial proportion of' the final m Es en line 0. sf g g gi Solvent Solvent Damn tmflcafim, m ga cogeneric reaction mixture. .Vanous suggestions (e a) e p have been made as to the nature of these compounds, such as being cyclic polymers of pro- 245 129 pylene oxide, dehydration products with the ap- 522 3 f 5 pearance of a vinyl radical, or isomers of propyl- 271 148 g ene oxide or derivatives thereof, 1. e., of an alde- 18 "5 hyde, ketone, or allyl alcohol. In some instances, 254 g i an attempt to react the stoichiometric amount 5 E3 8 of a polycarboxy acid with the oxypropylated de- 332 if: rivative results in an excess of the carboxylated 227 145 4.4 reactant, or the reason that apparently under. gig 32 W 3-? conditions of reaction, less reactive hydroxyl radi- 234 144 cals are present than indicated by the hydroxyl 32 g 40 value. Under such circumstances, there is simply' 223 141 10% "3'5 a residue of the carboxylic reactant which can 219 143 2% be removed by filtration, or, if desired, the esteri- 230 14s 10 3.5 230 148 5% fication procedure can be repeated, using an apgg propriately reduced ratio of carboxylic reactant.

4 Even the determination of the hydroxyl value The procedure for manufacturing the esters has been illustrated by preceding examples. If, for any reason, reaction does not take place in a manner that is acceptable, attention should be directed to the following details:

(a) Recheck the hydroxyl or acetyl value of the oxypropylated primary amines of the kind specified and use a stoichiometrically equivalent amount of acid;

(b) If the reaction does not proceed with reasonable speed, either raise the temperature indicated, or else extend the period of timeup to 12 or 16 hours, if need be;

(c) If necessary, use of para-toluene sulfonic acid, or some other acid as a catalyst;

(01) If the esterification does not produce a clear product, a check should be made to see if an inorganic salt such as sodium chloride or sodium sulfate is not precipitating out.

Such salt should be eliminated, at least for exploration experimentation, and can be removed by filtering. Everything else being equal, as the size of the molecule increases and the reactive hydroxyl radical represents a smaller fraction of the entire molecule, more difiiculty is involved in obtaining complete esterification.

Even under the most carefully controlled conditions of oxypropylation involving comparatively low temperatures and long time of reaction, there are formed certain compounds whose composition by conventional procedure leaves much to be desired, due, either to the cogeneric materials previously referred to, or, for that matter, the

presence of any inorganic salts or propylene oxide;

Obviously, this oxide should be eliminated.

The solvent employed, if any, can be removed from the finished ester by distillation, and particularly vacuum distillation. The final products or liquids are generally pale reddish amber to reddish black in color, and show moderate vis-- cosity. They can be bleached with bleaching clays, filtering chars, and the like. However, for the purpose of demulsification or the like, color is not a factor and decolorization is not justified.

In the above instances, I have permitted the solvents to remain present in the final reaction mass. In other instances, I have followed the same procedure, using decalin or a mixtureof decalin or benzene in'the same manner and ultimately removed all the solvents by vacuum dis tillation. Appearances of the final products are much the same as the diols before esterification,

and in some instances were somewhat darker incolor and had a more reddish castand were perhaps somewhat more viscous.

PART 3 Previous reference has been made to the fact,

lecular weight, for example, have been esterified with dic-arboxy acids and employed as demulsifying agents. The herein described compounds are different from such diols although both, it is true, are high molecular weight dihydroxylated compounds. The instant compounds have prescut a nitrogen atom and are possibly susceptible to certain changes in structure which are not present in an ordinary diol. It seems reasonable to assume that the orientation of such molecules is effected by the presence of such particular structure insofar that presumably it would lead to association by hydrogen bonding or some other effect.

Regardless of what the difference may be the fact still remains that the compounds of the kind herein described may be, and frequently are, 15% or better on a quantitative basis than the simpler compound previously described, and demulsify faster and give cleaner oil in many instances. The method of making such comparative tests has been described in a booklet entitled Treating Oil Field Emulsions, .used in the Vocational Training Course, Petroleum Industry Series, of the American Petroleum Institute.

It may be well to emphasize also the fact that oxypropylation does not produce a single compound but a cogeneric mixture. The factor involved is the same as appears if one were oxypropylating a monohydric alcohol ora glycol. Momentarily, one may consider the structure of a polypropylene glycol, such as polypropylene glycol of 2000 molecular weight. Propylene glycol has a primary alcohol radical and a secondary alcohol radical. In this sense the building unit which forms polypropylene glycols is not symmetrical. Obviously, then, polypropylene glycols can be obtained, at least theoretically, in which two secondary alcohol groups are united or a secondary alcohol group is united to aprimary alcohol group, etherization being involved, of course, in each instance.

Usually no effort is made to differentiate between oxypropylation taking place, for example, at the primary alcohol radical or the secondary alcohol radical. Actually, when such products are obtained, such as a high molal polypropylene glycol or the products obtained in the manner herein described one does not obtain a single derivative such as I-lOiROMH in which n has one and only one value, for instance, l4, 15 or 16, or the like. Rather, one obtains a cogeneric mixture of closely related or touching homologues. These materials invariably have high molecular weights and cannot be separated from one another by any known procedure without decomposition. The properties of such mixture represent the contribution of the various individual members of the mixture. On a statistical basis, of course, 11. can be appropriately specified. For practical purposes one need only consider the oxypropylation of a monohydric alcohol because in essence this is substantially the mechanism involved. Even in such instances where one is concerned with a monohydric reactant one cannot draw a single formula and say that by following such procedure one can readily obtain 80% or 90% or 100% of such compound. However, in the case of at least monohydric initial reactants one can readily draw the formulas of a large number of compounds which appear in some of the probable mixtures or can be prepared as components and mixtures whichv are manu factured conventionally,

' curves for linear polymers.

' representing both which n has a single definite value, and also with Simply by way of illustration reference is made to U. S. Patent No. 2,549,434 dated April 17, 1951, to De Groote, Wirtel and Pettingill.

However, momentarily referring again to a monohydric initial reactant it is obvious that if one selects any such simple hydroxylated compound and subjects such compound to oxyalkylation, such as oxyethylation, or oxypropylation, it becomes obvious thatone is really producing a polymer of the alkylene oxide except for the terminal group. This is particularly true where the amount of oxide added is comparatively large, for instance, 10, 20, 30, 40, or 50 units. If such compound is subjected to oxyethylation so as to introduce 30 units of ethylene oxide, it is well known that one does not obtain a single constituent which, for the sake of convenience, may be indicated as RO(C2H40)30OH. Instead, one obtains a cogeneric mixture of closely related homologues, in which the formula may be shown as the following, RO'(C2H4O) 71H, wherein n, asfar as the statistical average goes, is 30, but the individual members present in significant amount may vary from instances Where n has a value of 25, and perhaps less, to a point where n may represent 35 or more. Such mixture is, as stated, a cogeneric closely related series of touching homologous compounds. Considerable investigation has been made in regard to the distribution the ability to describe how to make the product under consideration and how to repeat such production time after time without difficulty, it is necessary to resort to some other method of description, or else consider the value of n, in

formulas such as those which have appearedpreviously and which appear in the claims, as individual constituents in the understanding that n represents the average statistical value based on the assumption of completeness of reaction.

This may be illustrated as follows: Assume that in any particular example the molal ratio of the propylene oxide to furfurylamine, or other specified amine is 30 to 1. Actually, one obtains products in which n probably varies from 10 to 20, perhaps even further. The average value, however, is 15, assuming, as previously stated, that the reaction is complete. The product described by the formula is best described also in terms of method of manufacture.

PART 4 alcohol, denatured alcohol, propyl alcohol, butyl alcohol, hexyl alcohol, octyl alcohol, etc., may

Attention is directedbe employed as diluents. Miscellaneous solvents such as pine oil, carbon tetrachloride, sulfur dioxide extract obtained in the refining of petroleum, etc., may be employed as diluents. Similarly, the material or materials employed as the demulsifying agent of my process may be admixed with one or more of the solvents customarily used in connection with conventional demulsifying agents. Moreover, said material or materials may be used alone or in admixture with other suitable well-known classes of demulsifying agents.

It is well known that conventional demulsifying agents may be used in a water-soluble form, or in an oil-soluble form, or in a form exhibiting both oiland water-solubility. Sometimes they may be used in a form which exhibits relatively limited oil-solubility. However, since such reagents are frequently used in a ratio of l to 10,000 or 1 to 20,000, or 1 to 30,000, or even 1 to 40,000, or 1 to 50,000 as in desalting practice, such an apparent insolubility in oil and water is not significant because said reagents undoubtedly have solubility within such concentrations. This same fact is true in regard to the material or materials employed as the demulsifying agent of my process.

In practicing my process for resolving petroleum emulsions of the water-in-oil type, a treating agent or demulsifying agent of the kind above described is brought into contact with or caused to act upon the emulsion to be treated, in any of the various apparatus now generally used to resolve or break petroleum emulsions with a chemical reagent, the above procedurebeing used alone or in combination with other demulsifying procedure, such as the electrical dehydration process.

One type of procedure is to accumulate a volume of emulsified oil in a tank and conduct a batch treatment type of demulsification procedure to recover clean oil. In this procedure the emulsion is admixed with the demulsifier, for example by agitating the tank of emulsion and slowly dripping demulsifier into the emulsion. In some cases mixing is achieved by heating the emulsion while dripping in the demulsifier, depending upon the convection currents in the emulsion to produce satisfactory admixture. In

a third modification of this type of treatment, a-

circulating pump Withdraws emulsion from, c. g., the bottom of the tank, and reintroduces it into the top of the tank, the demulsifier being added, for example, at the suction side of said circulating pump.

In a second type of treating procedure, the

demulsifier is introduced into the well fluids at the well-head or at some point between the wellhead andthe final oil storage tank, by means of an adjustable proportioning mechanism or proportioning pump. Ordinarily the flow of fluids through the subsequent lines and fittings suffices to produce the desired degree of mixing of demulsifier and emulsion, although in some instances additional mixing devices may be introduced into the flow system. In this general procedure, the system may include various mechanical devices for withdrawing free water, separating entrained water, or accomplishing quiescent settling of the chemicalized emulsion. Heating devices may likewise be incorporated in any of the treating procedures described herein.

A third type of application (down-the-hole) of demulsifier to emulsion is to introduce the demulsifier either periodically or continuously in diluted or undiluted form into the well and to allow it to come to the surface with the well fluids, and then to flow the chemicalized emulsion through any desirable surface equipment, such as employed in the other treating procedures. This particular type of application is decidedly useful when the demulsifier is used in connection with acidification of calcareous oil-bearing strata, especially if suspended in or dissolved in the acid employed for acidification.

In all cases, it will be apparent from the foregoing description, the broad process consists simply in introducing a relatively small proportion of demulsifier into a relatively large proportion of emulsion, admixing the chemical and emulsion either through natural flow or through special apparatus, with or without the application of heat, and allowing the mixture to stand quiescent until the undesirable water content of the emulsion separates and settles from the mass.

The following is a typical installation.

A reservoir to hold the demulsifier of the kind described (diluted or undiluted) is placed at the well-head where the efiluent liquids leave the well. This reservoir or container, which may vary from 5 gallons to 50 gallons for convenience, is connected to a proportioning pump which injects the demulsifier drop-Wise into the fluids leaving the well. Such chemicalized fluids pass through the flowline into a settling tank. The settling tank consists of a tank of any convenient size, for instance, one which will hold amounts of fluid produced in 4 to 24 hours (500 barrels to 2000 barrels capacity), and in which there is a perpendicular conduit from the top of the tank to almost the very bottom so as to permit the incoming fluids to pass from the top of the settling tank to the bottom, s that such incoming fluids do not disturb stratification which takes place during the course of demulsification. The settling tank has two outlets, one being below the water level to drain off the water resulting from demulsification or accompanying the emulsion as free water, the other being an oil outlet at the top to permit the passage of dehydrated oil to a second tank, being a storage tank, which holds pipeline or dehydrated oil. If desired, the conduit or pipe which serves to carry the fluids from the well to the settling tank may include a section of pipe with baflles to serve as a mixer, to insure thorough distribution of the demulsifier throughout the fluids, or a heater for raising the temperature of the fluids to some convenient temperature, for instance, to F., or both heater and mixer.

Demuls'ification procedure is started by simply setting the pump so as to feed a comparatively large ratio of demulsifier, for instance, 1:5,000. As soon as a complete break or satisfactory demulsification is obtained, the pump is regulated until experience shows that the amount of demulsifier being added is just sufficient to produce clean or dehydrated oil. The amount being fed at such stage is usually 1:10,000, 1:15,000, 1:20.000, or the like.

In many instances the oxyalkylated products herein specified as demulsifiers can be conveniently used without dilution. However, as previously noted, they may be diluted as desired with any suitable solvent. For instance, by mixing '75 parts by weight of the product of Example 12?) with 15 parts by weight of xylene and 10 parts by weight of isopropyl alcohol, an excellent demulsifier is obtained. Selection of the solvent will vary, depending upon the solubility characteristics of the oxyalkylated product, and of course will be dictated in part by economic considerations, i. e., cost.

As noted above, the products herein described may be used not only in diluted form, but also may be used admixed with some other chemical demulsifier. A mixture which illustrates such combination is the following:

Oxyalkylated derivative, for example, the prodnet of Example 12b, 20%;

A cyclohexylamine salt of a polypropylated napthalene monosulfonic acid, 24%;

An ammonium salt of a polypropylated napthalene monosulfonic acid, 24%;

A sodium salt of oil-soluble mahogany petroleum sulfonic acid, 12%;

A high-boiling aromatic petroleum solvent, 15%;

Isopropyl alcohol,

The above proportions are all weight percents.

PART 5 As pointed out previously, the final product obtained is a fractional ester having free carboxyl radicals. Such product can be used as an intermediate for conversion into other derivatives which are effective for various purposes, such as the breaking of petroleum emulsions of the kind herein described. For instance, such product can be neutralized with an amino so as to increase its water-solubility such as triethanolamine, tripropanolamine, oxyethylated triethanolamine, etc. Similarly, such product can be neutralized with some amine which tends to reduce the water solubility such as cyclohexylamine, benzylamine, decylamine, tetradecylamine, octadecylamine, etc. Furthermore, the residual carboxyl radicals can be esterified with alcohols, such as low molal alcohols, methyl, ethyl, propyl, butyl, etc., and also high molal alcohols, such as octyl, decyl, cyclohexanol, benzyl alcohol, octadecyl alcohol, etc. Such products are also valuable for a variety of purposes due to their modified solubility. This is particularly true where surface-active materials are of value and especially in demulsification of water-in-oil emulsion.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. A process for breaking petroleum emulsions of the water-in-oil tvpe characterized by subjectins, the emulsion to the action of a demulsifier including hydrophile synthetic products, said hydrophile synthetic products being characterized by the following formula R is the radical of a polycarboxy acid COOH in which n" has its previous significance, with the further proviso that the parent dihydroxy compound prior to esterification be water-insoluble and kerosene-soluble.

2. A process for breaking petroleum emulsions 18 of the water-in-oil type characterized by subjecting the emulsion to the action of a demulsifier including hydrophile synthetic products; said hydrophile synthetic products being characterized by the following formula in which n and n are whole numbers, with the proviso that it plus 1!. equals a sum varying from 15 to and R is the radical of a dicarboxy acid;

in which n and n are whole numbers, with the proviso that n plus n equals a sum varying from 15 to 80; and R is the radical of a dicarboxy acid;

said dicarboxy acid having not more than 8 carbon atoms; with the further proviso that the parent dihydroxy compound prior to esterification be water-insoluble and kerosene-soluble.

4. The process of claim 3 wherein the dicarboxy acid is phthalic acid.

5. The process of claim 3 wherein the dicarboxy acid is maleic acid.

6. The process of claim 3 wherein the dicarboxy acid is succinic acid.

'7. The process of claim 3 wherein the dicarboxy acid is citraconic acid.

8. The process of claim 3 wherein the dicarboxy acid is diglycolic acid.

his MELVIN DE GROOTE.

mark Witnesses to the signature:

W. C. ADAMS, I. S. DE Groom.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,243,329 De Groote et a1 May 2'7, 1941 2,295,169 De Groote et a1 Sept. 8, 1942 2,562,878 Blair Aug. 7, 1951 

1. A PROCESS FOR BREAKING PETROLEUM EMULSIONS OF THE WATER-IN-OIL TYPE CHARACTERIZED BY SUBJECTING THE EMULSION TO THE ACTION OF A DEMULSIFIER INCLUDING HYDROPHILE SYNTHETIC PRODUCTS, SAID HYDROPHILE SYNTHETIC PRODUCTS BEING CHARACTERIZED BY THE FOLLOWING FORMULA 